You can use the Keyword Planner to get keyword ideas and traffic estimates for your campaigns. Even if you are not interested in running paid campaigns, you can use the tools to optimize your organic search rankings.English: Google Logo officially released on May 2010 (Photo credit: Wikipedia)

Using the free services, the Google Keyword Planner can assist you with the following:

Search for new keyword ideas

Get search volume for a list of keywords

Get traffic estimates for a list of keywords

To get a better feel for the system, Google released a video run-through